NTDA Development and Operational Demonstration

Transcription

1 NTDA Development and Operational Demonstration FY 2007 Year-End Progress Report on Turbulence RT Tasks and Provided in fulfillment of Deliverables E1, E1 and E2 Submitted by The National Center for Atmospheric Research

2 Introduction In FY 2007, NCAR was given Technical Direction by the FAA s Aviation Weather Research Program Office to perform continued research and development and an operational demonstration of the NEXRAD Turbulence Detection Algorithm (NTDA) under task , NTDA Development and task , NTDA Operational Demonstration. NTDA research and development efforts resulted in the both delivery to the National Weather Service (NWS) Radar Operations Center (ROC) in February 2007 of the first operational version of the algorithm, NTDA-1, and also the initial development of NTDA-2. The FY07 operational demonstration followed successful NTDA demonstrations in FY05 and FY06, but involved a significant expansion in the size of the domain and the number of pilots involved in experimental cockpit uplinks. This report summarizes the research and development and operational demonstration activities in fulfillment of Turbulence Research Team (TRT) deliverables E1, E1 and E2. The NTDA-1 approval and delivery activities are described in a separate report on Advanced Weather Radar Techniques Research Team Task , NTDA Implementation in NEXRAD OpenRPG/CODE. FY07 NTDA Development Efforts In early FY07, data collected from individual radars during the summer 2006 real-time demonstration were compared with aircraft in situ turbulence reports and extensively analyzed. The results were used along with case studies and simulations to tune the NTDA s interest maps. The SW-to-EDR table used by the NTDA was modified based on these empirical results. In addition, the data analysis prompted simulation studies that identified a positive bias in the NEXRAD ORDA spectrum width estimator (see the AWRT Turbulence Report for more information). If a more accurate spectrum width estimator could be implemented on the 1

3 NEXRADs, it would permit the NTDA to more accurately measure low turbulence values, increase the NTDA s coverage, and might further decrease the FAR for the NTDA s detection of moderate or severe turbulence. Acceptance testing based on case study analyses was performed in support of AWRT PDT Task to verify that the NTDA implementation software was producing correct results. This process led to the identification of bugs in the computation of two QC fields that were subsequently fixed. Statistical and case study analyses, along with examination of simulation data produced under AWRT PDT task , were used to finalize NTDA quality control interest maps for each NEXRAD volume coverage pattern (VCP), including Build 9 SZ-2 VCPs 211, 212 and 221. An analysis of radar/aircraft comparison data from the summer 2006 real-time demonstration was used to determine the empirically optimal SW-to-EDR scale factor table for use by the NTDA. In support of AWRT PDT task , case studies were performed to verify that the ORPG/CODE NTDA software implemented the algorithm correctly, one element of the testing that preceded the NTDA package delivery to the Radar Operations Center on February 1 and package update (including VCP 211, 212 and 221 support) on February 26. An analysis of the impact of NEXRAD spectrum width measurement errors on NTDA accuracy and coverage was completed and included in a presentation to the NEXRAD Technical Advisory Committee on March 28 in Norman. An alternative poly-pulse spectrum width estimator was also presented, along with a recommendation that the NEXRAD Technical Requirement for spectrum width be revised. 2

4 Software was written to read the clutter bypass map and clutter map from NEXRAD Level II data within the ORPG. New interest maps were added to reduce spectrum width confidence for pixels for which clutter filtering was applied and for pixels contaminated by overlaid clutter. While a comprehensive study has not been performed, this addition to the NTDA quality control procedure shows promise in mitigating EDR over-estimates that occasionally occur in the region just past the radar s unambiguous range. The initial refactoring of the NTDA software, a first step in the development of NTDA-2, has been completed. NTDA-2 will support specification of interest maps and SW-to-EDR tables for each VCP, elevation, and PRF, accommodate upcoming NEXRAD changes, support new quality control procedures based on dual-pol data, and may incorporate a velocity structure function method for EDR retrieval. As a result, NTDA-2 will provide greater accuracy and significantly increased coverage, including turbulence below 10,000 ft. NCAR continues to actively participate in the NWS OSIP approval process for the NTDA data dissemination and operational mosaic. Detailed information on this activity may be found in the FY07 AWRT Turbulence Report. The operational demonstration continues to provide cases in which suspicious behavior is evident. Recently, a case was investigated in which data from several adjacent radars were contaminated simultaneously. After verifying that the same contamination occurred in the Level II data archived at the NCDC, a close examination suggested that the contamination was due to a source radio-frequency interference (RFI) source located in north central Kansas. Cases like this are being used to motivate additional quality control procedures within the NTDA. 3

5 FY07 NTDA Operational Demonstration The Turbulence Remote Sensing operational demonstration system was run once again at NCAR for the convective summer season. In addition to supplying experimental data to users in a proof-of-concept of the usefulness of timely detection of in-cloud turbulence, this demonstration has provided the ability to comprehensively monitor a large number of radars for suspicious data or poor performance conditions that have led directly into case studies and NTDA improvements. Data from the real-time demonstration will soon be used for both diagnosis of convectively-induced turbulence (D-CIT) and Graphical Turbulence Guidance Nowcast (GTGN) development. Feedback from end-users has been helpful in identifying cases for further study and determining how to modify the product to provide the most useful information. In addition, nationwide and international press coverage of this project has provided a good news story about the FAA s aviation weather work and provided an opportunity for potential collaborators and private weather service vendors to make contact with the NTDA developers. The UCAR press release on the NTDA, which was released on September 6, may be found at The story has been picked up by more than 20 media outlets around the world; see for a few of the stories. Optimizations applied to the core NTDA algorithm before the season allowed for 15 new NEXRAD radars to be added to the existing four operational servers. At the end of June two new dual-quad core servers were acquired for the system. These were added to operational system, with 22 radars run on each new server. This brought the operational system to a total of 83 radars covering a domain from the eastern seaboard to the Front Range of Denver and from the Canadian border down to the Gulf of Mexico. 4

6 Due to the large increase in the amount of data with a three and a half times increase in the number of radars, the entire system had to be modified to store data as encoded bytes instead of short integers. The mosaic domain also had to be split into two separate domains, one above the northern Tennessee border and one below. The two sub-domains are then stitched together to form a single domain for use in viewing and uplinking. This split kept the total lag time, the time it takes data to be read, processed and sent to ARINC for uplink, to under one minute, even during large storm activity, as is needed for accurate turbulence messages in aircraft. The Java web-based display was upgraded to include the larger domain of coverage, the new radars, and updated colorscale, and several minor improvements. The images below depict screen displays for 2230 UTC 28 September 2007, including zoom in and vertical crosssection images for the storm in western Kansas. 5

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12 The cockpit uplink of customized maps of in-cloud turbulence was continued and expanded in 2007 (see the draft Flight Crew Bulletin written by NCAR in Appendix A). During the 2006 operational demonstration system there had been a total of only five different United pilots testing the system for the whole year. This year at the beginning of July all Line Check Airmen at United were invited to participate and a significant increase in the number of registrations during July and August was observed. With the increase in domain and participating pilots a huge increase occurred in the number of uplinked messages. Feedback from pilots so far has been nearly all positive with high regard in the convective / turbulence accuracy. Recently Capt. Rocky Stone, taking off from Denver said, Very accurate turbulence information. The map was a little off, as we received an ATC re-route just prior to the map being uplinked. The image that Capt. Stone was referring to is shown below. 11

13 /EXPERIMENTAL TURBULENCE FI UAL /AN N UA <UPLINK> -- 3 Sep :44: 3Z FL 3 orient. 298 deg '+'=waypoint, '*'=route, 'X'=aircraft at 4.8N, 1 4.7W ' '=no_data, 'o'=smooth, 'l'=light, 'M'=mod, 'S'=severe (43 to CKW) * o oo lol lll lll llll*l lll llllll* lll llllllo*o lll lllllo*o lll +LAR llllo+o lol ooo * lll o * lll lll l llll * lll ollllllll l * llo llloolllllol * lll llllll lllo * lll 4 llllo ll * lloo llm lllloooll * olllllll llm lllooo * l lll llolllollllllll lll loo oo l*llllo lllololllllllllllll llm oollol*lllloommllloollllllllllll lll oollo*lllllllmmlllollllllllllllll lll l ooolll*lllllllllllllolllllllllllll lll l ooooooo*llllllllllllllolllllllllllll lll l loloool*llllllllllllllloollllllllll lll lllool*lllllllllllllllllllllloolloo lll lolool*ollllolll lllooollo lll oooo*oooolooll llllo lll oooo*ooooooo ll lll oo* ooo llo +YAMMI o+ lo * lo o lll l lll * l valid X Left Z (6 from DEN) Right 4 12

14 The sending of uplink messages through ARINC had some problems early on this season as socket communicates between NCAR and ARINC failed sporadically without notice. Error checking and notification code was quickly implemented after discovery in mid July. The problem has been minimized and a full solution is being worked on between the two companies. Examination for abnormal cases in both the NTDA algorithm and the ASDI aircraft route decoding code were made easier by monitoring both in real-time. For the NTDA algorithm an automated poor-performance detecting algorithm that uses the United in-situ EDR data to detect anomalies was run during the season. Once cases were detected NTDA data overlays with in-situ data were plotted automatically for study. Using this automated detecting algorithm with the real time system has greatly helped us discover areas for NTDA algorithm improvement. For aircraft route decoding it is extremely difficult to discover an improperly decoded FAA flight plan as there is no verification data to work from. However with pilots registering their flights and the ability to talk to them about their actual routes we have been able to discover and fix the few remaining ambiguous route decoding cases. This well-tested ASDI ingest and decoding capability will be useful when ASDI data are used for other purposes for instance, filling in the flight path between reported turbulence events in SouthWest EDR data. 13

15 Appendix A: United Flight Crew Bulletin for the Uplink Demonstration (redacted) Experimental Turbulence Remote Sensing Uplinks BACKGROUND The experimental Turbulence Remote Sensing (TRS) system provides a graphical map of in-cloud turbulence along the cleared route of flight out to 100 nautical miles. The graphical map is uplinked directly to the ACARS printer. The system was developed by the National Center for Atmospheric Research and uses information derived from NEXRAD radar data to measure atmospheric turbulence. On the uplink messages, turbulence is depicted by characters representing smooth air, light turbulence, moderate turbulence, or severe turbulence based on its anticipated effect on a medium-sized (e.g., Boeing 757) airplane flying at cruise speeds. In general, smaller aircraft may be expected to experience more intense effects from atmospheric turbulence while larger aircraft or slower airspeeds may lessen the effects. Since it is derived from NEXRAD data, the turbulence map is only applicable for incloud regions where radar reflectivity is sufficiently strong to return reliable measurements and where signal contamination due to ground clutter is minimal. As a result, this system does not detect clear-air turbulence. Therefore, no data should not be mistaken as meaning no turbulence. It is typical for the majority of each turbulence message to be blank, representing no data. OPERATING PROCEDURES The TRS uplink is an experimental weather product. Thus, conventional weather information and what is displayed on the airborne weather radar are still governing. The intent of this product is to raise crew situational awareness about turbulence ahead, not to circumnavigate it. However, the printouts may be used to determine when to turn on the seat belt sign or ask flight attendants to be seated. The turbulence information is automatically generated and will come over the ACARS printer as character graphics. The graphics are intuitive to read and interpret and include a simple legend. The primary altitude (rounded to the nearest multiple of 3,000 feet) is listed at the top of the printout. The right side of the printout is a plan view of turbulence at the primary altitude from 40 miles left to 40 miles right of the flight path out to 100 miles. Along the left margin of the printout is a vertical cross-section view of turbulence in 3,000-foot increments from 9,000 feet below to 9,000 feet above the primary altitude. The vertical view depicts the maximum measured turbulence within 14 miles left or right of the centerline (approximately 1/3 of the plan view map width). 1

16 The system runs automatically. Messages are generated at 5-minute intervals whenever the system is operational, the aircraft is in the uplink demonstration area of coverage (the green polygon in the map below), the aircraft altitude is above 10,000 feet, and significant turbulence is detected near the route of flight. Blank areas of the printout mean no data, not no turbulence. The turbulence information represents what was detected using the NEXRAD data available at the time of uplink. Storm motion and evolution may significantly change the location and intensity of in-cloud turbulence in the time it takes the data to be processed and transmitted. This is a situational awareness product so there is no indication of system failure. The lack of an ACARS printout does not mean there is no hazardous weather ahead. The map below shows the TRS mosaic coverage area, the uplink demonstration domain, and the locations of the NEXRADs used to produce the TRS product: Sample ACARS printout: 2

17 /EXPERIMENTAL TURBULENCE FI UAL /AN N UA UPLINK May 2ØØ6 22:18:35Z FL 33Ø orient. 267 deg '+'=waypoint, '*'=route, 'X'=aircraft at 38.8N, 81.ØW ' '=no_data, 'o'=smooth, 'l'=light, 'M'=mod, 'S'=severe (57 to FLM) Ø8Ø * oool * ooool ll * ooool * ooooo * ooo * MMM MMM * MMM MMMM * MMM +HNN MM + M MMM l Ø4Ø llll * lll l +LAYED llll + llm lll l llll * llmll lll l llll * lll MMM lll * lll MMM llm lll l lllm lll ll llll lll ll llll lll ooo llll lll o ooooo llll lll l oolll lllll lll l oolll ll loo o * loo o * ooo oo * ooo o * ooo oo valid X Ø +9Ø Left 4Ø 2215Z (39 from STEVY) Right 4Ø Pilot feedback at: +9,000 ft +6,000 ft +3,000 ft primary altitude level (always blank) 3,000 ft 6,000 ft 9,000 ft primary altitude (a multiple of 3,000 ft) 3

18 FLIGHT REGISTRATION To register a flight to receive the experimental TRS uplinks, please visit the site: You will be prompted to enter the Flight Number, Takeoff Date, Destination and Nose Number for each flight that you wish to be eligible to receive uplinks, along with (optionally) your contact information. If your equipment changes or the flight number is modified to an 8,000 or 9,000 number, you will need to revisit the site and update the flight information. If you no longer wish a previously registered flight to receive uplinks, it may be deleted. Flights originating outside the US are currently not supported. FEEDBACK Feedback on the uplink messages is desired via an electronic questionnaire available at: The questionnaire allows a pilot to browse through all the messages generated for a flight, to score those that were uplinked, and to provide overall comments for the flight. The primary purpose of the feedback is to assess the value and accuracy of the weather products. Any personal information requested is solely for the purpose of follow-up should more information be needed. Your support is greatly appreciated. United Airlines Flight Ops Contact: Captain Rocky Stone, DENTK Chief Technical Pilot rocky.stone@united.com Unitel NCAR Contact: Dr. John Williams NCAR Research Applications Laboratory P.O. Box 3000, Boulder, CO jkwillia@ucar.edu Voice: Fax: